Robert Cardillo, a former director of the National Geospatial-Intelligence Agency (NGA), authored a December 1 piece for Defense One entitled “We Need a Backup for GPS. Actually, We Need Several of Them.” Mr. Cardillo states that “no one system can sufficiently mitigate all of the threat vectors and simultaneously meet the unique demands of our 16 critical infrastructure sectors.” He goes on to support the goal of Executive Order 13905 as “encourag[ing] the private sector to adopt alternative-PNT solutions,” and suggest that “[i]t will probably be necessary for the government to offer additional incentives to send a clearer market signal to spur widespread adoption of APNT.”